# include <stdio.h>
int main(void)
{
	int n,x,y,a=0;
	scanf("%d %d %d",&n,&x,&y);
	
	if(y%x==0)
		a=y/x;
	else
		a=y/x+1;

	printf("%d\n",n-a);

	return 0;
}